Added caching to the predict views.

Needs to have a cache backend set up in the settings. You can use a dummy
one before setting up a real one.

See: https://docs.djangoproject.com/en/1.5/topics/cache

Dummy cache:

CACHES = {
    'default': {
        'BACKEND': 'django.core.caches.backends.dummy.DummyCache'
    }
}
Merge pull request #73 from Prillan/cache

Added caching to the predict views.